Quantification of 5-aminolevulinic acid by CE using dynamic pH junction technique

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Quantification of 5-aminolevulinic acid (ALA) is crucial for various applications.
• Conventional capillary electrophoresis (CE) methods may lack sufficient sensitivity and speed.

Purpose of the Study:

• To develop a rapid and highly sensitive online dynamic pH junction preconcentration method for ALA quantification by CE.
• To improve the sensitivity and efficiency of ALA analysis compared to traditional CE techniques.

Main Methods:

• Development of an online dynamic pH junction preconcentration technique utilizing a pH 9.3 borate buffer and a pH 2.5 phosphate buffer.
• Hydrodynamic injection of a sample plug into an uncoated fused-silica capillary.
• Application of a 24 kV separation voltage for CE analysis.
• Validation of linearity, reproducibility, and limit of detection (LOD).

Main Results:

• Achieved separation time of less than 6 minutes for ALA.
• Demonstrated excellent linearity (R² = 0.9991) from 0.01 to 6.5 mg/mL.
• Reported high reproducibility with relative standard deviations (RSDs) of 2.5% for peak area and 0.6% for migration time.
• Obtained a low LOD of 1.0 μg/mL.
• Achieved over 50-fold sensitivity improvement compared to conventional CE.
• Showed good agreement with HPLC results (r = 0.94) for pharmaceutical formulations.

Conclusions:

• The developed online dynamic pH junction CE method provides a sensitive, rapid, and reproducible approach for ALA quantification.
• This method offers a significant improvement in sensitivity, making it suitable for analyzing ALA in pharmaceutical samples.
• The technique is a valuable alternative to existing methods like HPLC for ALA determination.